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# How do you identify cyclic coordinates in Lagrangian?

## How do you identify cyclic coordinates in Lagrangian?

If a particular coordinate does not appear in the Lagrangian, it is called ‘Cyclic’ or ‘Ignorable’ coordinate. A bead is free to slide along a frictionless hoop of radius R. The hoop rotates with constant angular speed around a vertical diameter. Find the equation of motion for the position of the bead.

What is cyclic or ignorable coordinates?

A cyclic coordinate is one that does not explicitly appear in the Lagrangian. The term cyclic is a natural name when one has cylindrical or spherical symmetry. In Hamiltonian mechanics a cyclic coordinate often is called an ignorable coordinate .

### What do you understand by cyclic coordinates?

A generalized coordinate on which the Lagrangian of a system does not depend explicitly. Also known as ignorable coordinate.

What is cyclic coordinate with example?

If a generalized coordinate qj doesn’t explicitly occur in the Hamiltonian, then pj is a constant of motion (meaning, a constant, independent of time for a true dynamical motion). qj then becomes a linear function of time. Such a coordinate qj is called a cyclic coordinate.

## What is cyclic coordinate in Lagrangian?

A generalized coordinate that does not explicitly enter the Lagrangian is called a cyclic coordinate and the corresponding conserved quantity is called a constant of motion.

How do you write a Lagrangian equation?

The Lagrangian is L = T −V = m ˙y2/2−mgy, so eq. (6.22) gives ¨y = −g, which is simply the F = ma equation (divided through by m), as expected.

### What do you mean by Generalised coordinates?

In analytical mechanics, the term generalized coordinates refers to the parameters that describe the configuration of the system relative to some reference configuration. These parameters must uniquely define the configuration of the system relative to the reference configuration.

Why cyclic coordinates are called cyclic?

In a finite-size system this situation usually corresponds to the rotational degree of freedom, that’s why it is called “cyclic”.

## What are cyclic variables?

A cyclical variable is a fancy name for a feature that repeats cyclically.